Chemical reagents with reaction specificity for active sites of glycolytic enzymes are being tested and synthesized. The compounds being used resemble 3 carbon phosphorylated substrates found in glycolysis. With such reagents we intend to probe active sites of glycolytic enzymes to determine contact and catalytic groups within the active sites. Compounds being tested are (1) glycidol phosphate, an epoxide which reacts with a glutamic acid residue in triose phosphate isomerase and an unknown residue in enolase (currently being explored); (2) azide derivatives of tartronic acid phosphate, which are potential acylating reagents and, (3) N-Bromoacetyl derivatives of serine phosphate and isoserine phosphate, potential alkylating reagents.